Phosphate minerals hydroxylapatite, fl uorapatite and crandallite were identifi ed in nodules within phosphorites from Ervenik, Croatia. The minerals were identifi ed using optical microscopy, XRD, SEM and EDS analyses. The presence of fungi was recognized only in association with phosphate-rich phases. Fungal activity resulted in the dissolution of apatite, producing hollow crystals, particula...

Arachidonoyl-CoA synthetase was solubilized from a particulate fraction of calf brain and human platelets using 1% Nonidet P-40 and 10 mM EDTA. Arachidonoyl-CoA synthetase from both preparations was separated from nonspecific (long chain) acyl-CoA synthetase (EC 6.2.1.3) by chromatography on hydroxylapatite. To further substantiate that the two acyl-CoA synthetases are distinct proteins, we sol...

We report here the presence of two enzymatic activities associated with highly purified preparations of polynucleotide phosphorylase from Micrococcus luteus. The first, a nuclease activity, which is not separated from the phosphorylase on hydroxylapatite, may be due to substitution of H2O for phosphate in the phosphorolysis reaction. The second activity, a deoxyadenylate kinase, the bulk of whi...

Radioactive DNA ([(3)H]cDNA) complementary to the RNA of Mason-Pfizer monkey virus was used in molecular hybridization experiments to demonstrate sequence homology between its viral RNA and RNA of human malignant breast tumors. Hybridization products were analyzed by cesium sulfate equilibrium density centrifugation and hydroxylapatite chromatography. Seven of ten human malignant breast tumors ...

Arsenate (As5+) substitution in the hydroxylapatite structure was examined using a combination of crystallographic and spectroscopic techniques. Samples of hydroxylapatite, the As5+-substituted analog (synthetic johnbaumite), and five intermediate compositions were synthesized from solution. Synchrotron X-ray diffraction data show that all samples are single-phase, confirming complete substitut...